Preliminary Modeling Research Articles

Preliminary Thermal-Mechanical Coupled Modeling of U-10mo Helical Cruciform Fuel Rods Under the Unirradiated and High Burnup Irradiated Conditions

Preliminary Thermal-Mechanical Coupled Modeling of U-10mo Helical Cruciform Fuel Rods Under the Unirradiated and High Burnup Irradiated Conditions

At the source of the polarisation of auroral emissions: experiments and modeling

A polarised radiative transfer model (POMEROL) has been developed to compute the polarisation measured by a virtual instrument in a given nocturnal environment. This single-scattering model recreates real-world conditions (among them atmospheric and aerosol profiles, light sources with complex geometries at the ground and in the sky, terrain obstructions). It has been successfully tested at mid-latitudes where sky emissions are of weak intensity. We show a series of comparisons between POMEROL predictions and polarisation measurements during two field campaigns in the auroral zone, in both quiet and active conditions. These comparisons show the strength of the model to assess the aerosol characteristics in the lower atmosphere by using a mesospheric line. They also show that three main upper atmosphere emissions must be polarised: the green atomic oxygen line at 557.7 nm and the 1stN2+negative band at 391.4 nm (purple) and 427.8 nm (blue). This polarisation can be either created directly at the radiative de-excitation or may occur when the non-polarised emission crosses the ionospheric currents. We provide some of the potentialities it offers in the frame of space weather. These require refinements of the preliminary modeling approach considered in the present study.

Preliminary modelling of power losses in roller chain drive: application to single speed cycling

A quasi-static chain drive model is proposed. This model, consistent with single speed cycling application, applies to simple two sprocket drives. The kinematics of the transmission is determined, including the capture and release positions of the rollers and the influence of the polygonal effect. The tensions into the links and the contact forces (between rollers and sprocket) are then calculated based on the results of the kinematic analysis. Both chain strands are assumed to be straight and their tension are considered as imposed. An estimate of the roller displacement is proposed using existing studies on the relationship between loading conditions and roller positions along the sprocket tooth profile. The presented model, is then used to assess the contribution of both meshing and roller motion on the global efficiency of the drive. Calculations show that the magnitude of both loss sources is similar for a wide range of gear ratios and loading conditions. According to the presented results, the relative motion between the rollers and the sprocket tooth profile should be considered in future studies dedicated to chain drive efficiency.

Potential Greenhouse Gas Reductions Beyond Chile's Nationally Determined Contribution to 2030: Preliminary Modelling Results

Potential Greenhouse Gas Reductions Beyond Chile's Nationally Determined Contribution to 2030: Preliminary Modelling Results

Calculation of the economic efficiency of technological machines in the transition to continuous automated processes

In the paper, the authors determined that the introduction of automation significantly increases the efficiency of the machine at the lowest labor costs. However, many enterprises still use the equipment of the previous generation, since it is costly to upgrade the fleet. In this regard, the topical issue of improving the technological and economic efficiency of existing equipment arises. At the present stage of scientific and technological development, the main directions in the development of technological machines are: the transition to continuous automated processes, improving the quality of work, increasing the efficiency of using machines. The condition of the loading process research, working out the principles and installations of automatic control of supplying the loading machines with grabbing claws is considered. The experience of application of discrete control system with regulated upper and lower levels of turning in the adjusters of loading the grabbing part engines is based. The task of automatic control providing, with the consideration of occasional character of forming the load with the grabbing claws, the achievement of maximum productivity at keeping power and energy limits, is formulated. The necessary mathematical models and control algorithms, the peculiarity of which is preliminary modeling of the process, putting the results into the system of microprocessing control and consideration of deviations from the standard variant, are worked out. Using the offered system provides with the productivity increase up to 15%, increasing the reliability and reducing labour capacity in the machine control.

Insurance cases: analysis by machine learning

One of the main problems of insurance is fraud, when the client wants to get overpayments by distorting information about the insured event. However, traditional methods of insurance fraud combating require a lot of routine manual work and are not very effective. The paper proposes the development of a prototype of the insurance case monitoring system in order to detect fraud using machine-learning methods. The development was carried out on the example of a database of insurance cases, which has 38 variables and contains 1000 records of insurance claims. The dataset provides information on 1) client – 10 features; 2) insurance contract – 7 features; 3) incident – 21 features. Preliminary data processing, modeling and development of the monitoring system was carried out using the Python. Classifiers (logistic regression, gradient boosting and random forest) with different combinations of variables were built. For each model, the conjugation matrix, accuracy, specificity, sensitivity, and ROC curves were analyzed. Simulation results allowed to select 5 main variables for monitoring, 3 of which characterize the client, 2 – incident. The proposed monitoring system allows to identify the following patterns: 1) in most cases, fraudsters were managers and technical support staff; 2) customers, who were practicing chess or CrossFit, were more prone to fraud; 3) most of the fraud was recorded in severe damage; 4) in case of absence of contact with emergency services, a large amount of the claim indicated fraud.

An acoustic sensor technology to detect urine excretion

Excretion of urinary nitrogen (N) from grazing ruminants is the main source of N loss from grazed pastures. The aim of this study was to reduce farm N loss by harnessing between-cow variation in urine excretion using a non-invasive acoustic urine sensor technology. Acoustic sensors were attached to 100 cows in summer and autumn to detect the time and duration of urination events during the grazing of pasture. The acoustic classifier had good performance with an F1 statistic of 0.91 in the calibration study, and an F1 statistic of 0.87 in the validation study. The model for duration of urination had an R2 = 0.87 in the validation trial, and an R2 = 0.92 in the calibration trial. There was significant between-cow variation in urination frequency, duration and N load per event, with coefficients of variation of 10–30%. Two divergent cow groups (Low, High N load per event for fixed daily urine N excretion) were selected for independent validation using direct measurement of urine-N excretion on 20 cows. The divergent groups had similar total daily amounts of urine-N excreted (178 g N cow−1 day−1) but differed by 23% in the average amount of N per urination event, primarily driven by a 37% increase in urination frequency. Associated preliminary modelling predicted a 10% reduction in N leaching loss at the paddock scale in the Low group due to increased spread of urine. This highlights the potential for using a urine sensor as a new management tool to reduce environmental N losses from grazed pastoral systems.

High strength fiber reinforced one-part alkali activated slag composites from industrial side streams

This paper details the effect of fiber reinforcement on mechanical characteristics of by-products based one-part alkali activated material (AAM). Two different binder matrices were considered in this study, such as, plain slag, and ternary blended slag, to understand their efficiency in fiber reinforced system. These matrices were reinforced with 1% v/v of three different fibers (steel, glass and basalt) to improve the flexural performance of high strength mortar blends. Steel fiber reinforced one-part AAM outperforms mineral fibers in compressive strength contribution. The fracture energy of steel fiber reinforced compositions was roughly 4 times higher than that of mineral fiber reinforced materials. In addition, the flexural performance of ternary blended matrix was higher than that of slag-based composition regardless fiber types and properties. Finally, preliminary finite element modelling was considered to assess the applicability of the concrete damage plasticity constitutive model in predicting the nonlinear behavior of the developed composites. The numerical predictions proved the accuracy of the model with good agreement between experimental and numerical results.

КІНЕТОСТАТИЧНЕ ДОСЛІДЖЕННЯ ШАРНІРНИХ ПРОСТОРОВИХ МЕХАНІЗМІВ ГАЛТУВАЛЬНИХ МАШИН (ЧАСТИНА 1: ДОСЛІДЖЕННЯ МЕХАНІЗМУ З ДОДАТКОВОЮ РУХОМОЮ ЛАНКОЮ – КОРОМИСЛОМ)

Kinetostatic study of a statically determined hinged spatial mechanism without redundant (passive) connection with an additional movable link – a rocker arm of a machine for processing parts, in which the working container performs complex spatial movement. Methodology. The essence of the kinetostatic research was to determine the radial and axial components of the reactions in all rotational kinematic pairs of the hinged statically defined spatial mechanism of the machine for processing parts, when it is idling. The kinetostatic study was implemented using the SolidWorks 2016 computer-aided design system with preliminary 3D modeling of this machine design with an additional moving link – a rocker. Results. In the course of the kinetostatic study, 3D modeling of a machine with an additional movable link – a rocker arm in the SolidWorks 2016 computer-aided design system was carried out, the maximum values of the radial and axial components of reactions in all rotational kinematic pairs of the machine for processing parts were determined, the effect of changing the center distance of the intermediate connecting rod (working capacity ) on the increase in the maximum values of the reactions in all rotational kinematic pairs. Scientific novelty. The relationship between the center distance of the intermediate connecting rod (working capacity) and the change in the maximum values of the reactions in all rotational kinematic pairs of the machine for processing parts is determined. As a result, it becomes possible to determine the maximum permissible center distance of the intermediate connecting rod to ensure the durable operation of the machine. Practical significance. It is determined that the nature of the change in the maximum values of the radial and axial components of the reactions in each rotational kinematic pair of the spatial mechanism depends on the value of the coefficient characterizing the ratio of the center-to-center length of the intermediate connecting rod (working capacity) to the center-to-center length of the driving or driven connecting rods of the machine. The range of variation of this coefficient has been determined, within which it is rational to design this machine design. The results obtained can be used in the corresponding design bureaus of machine-building enterprises at the stage of designing tumbling equipment with a complex spatial movement of working containers.

Indolylarylsulfones bearing phenylboronic acid and phenylboronate ester functionalities as potent HIV‑1 non-nucleoside reverse transcriptase inhibitors

To explore the chemical space around the entrance channel of the HIV-1 reverse transcriptase (RT) binding pocket, we innovatively designed and synthesized a series of novel indolylarylsulfones (IASs) bearing phenylboronic acid and phenylboronate ester functionalities at the indole-2-carboxamide as new HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs) through structure-based drug design. All the newly synthesized compounds exhibited excellent to moderate potency against wild-type (WT) HIV-1 with EC50 values ranging from 6.7 to 42.6 nM. Among all, (3-ethylphenyl)boronic acid substituted indole-2-carboxamide and (4-ethylphenyl) boronate ester substituted indole-2-carboxamide were found to be the most potent inhibitors (EC50 = 8.5 nM, SI = 3310; EC50 = 6.7 nM, SI = 3549, respectively). Notably, (3-ethylphenyl)boronic acid substituted indole-2-carboxamide maintained excellent activities against the single HIV-1 mutants L100I (EC50 = 7.3 nM), K103N (EC50 = 9.2 nM), as well as the double mutant V106A/F227L (EC50 = 21.1 nM). Preliminary SARs and molecular modelling studies are also discussed in detail.

Evaluation of the efficiency of aerodynamic dampers based on preliminary numerical modeling

The article is devoted to the issues of ensuring the stability of large-span bridge structures by means of their aerodynamic damping. Aerodynamic damping allows you to change the nature of the wind flow around structures or their individual elements, which can significantly reduce the loads that cause the occurrence of various aeroelastic phenomena. Aerodynamic damping devices (fairings, deflectors) are based on the phenomenon of changes in the circulation of the wind flow around the structure, the purpose of their use, as a rule, is to disrupt regular vortex formation. The main problem when using these devices is the lack of recommendations for their selection and the need for costly experimental studies to assess their effectiveness for each specific bridge. One of the ways to reduce the time and cost of research is preliminary numerical modeling in specialized software systems. Within the framework of this study, the most common types of aerodynamic dampers have been analyzed, and typical designs of large-span beam bridges have been selected. For the selected structures, a preliminary numerical simulation was carried out in a two-dimensional formulation. Based on the results obtained, the most effective designs of deflectors and fairings were determined.

ENGINEERING OF DESIGN AND TECHNOLOGICAL PREPARATION OF PRODUCTION

The article deals with issues related to ensuring the quality of products and their reliability, which is provided, starting from the preliminary design, design, modeling, production and disposal. Thus, the reliability of the product design is evaluated at all stages of its life cycle. Two main periods of the life cycle are considered – the development and modeling of new products, the second - its development, production and implementation. When mastering the production of new equipment, an important place is given to the formation and development of technologies that also have their own life cycle and affect the profit and competitiveness of the manufactured product.

Model the structure of nano-modified aluminium alloy with the addition of boron carbide

Nanocomposite thin films based on Al-Si alloy with the addition of boron carbide (B4C) particles are widely used in various fields of modern high-tech industry. For their synthesis, the method of laser nanomodification was used, which made it possible to obtain samples with a dendritic structure. The parameters of laser radiation were selected on the basis of preliminary modeling of the temperature field of the system. To describe the ensemble of nanodendrites on the surface, we used modeling of their structure in variable phase field and temperature for the initial stages, as well as the approximation of diffusion-limited aggregation and fractal Brownian motion for subsequent time intervals. The model showed satisfactory adequacy, estimated on the basis of the ratio of fractal dimensions of experimental and model structures. The proposed approach can be useful for predicting the structure of nanomodified aluminum alloys with various additions.

New photometry of 12 ultrashort-period late-type binary stars

ABSTRACT Candidate late-type binary stars were selected on the basis of their red g − i and r − z colours, and short (0.1159–0.2059 d) published periods. At least one cycle of variation of each star was observed in the RC and IC bands. For the five brightest stars, observations were also obtained in V. Typically ∼17 standardized photometric measurements of each of the stars, ranging over the optical and infrared, are available from various surveys. These were used to accurately determine the reddenings and effective temperatures. In all but one case Gaia parallaxes are available, so that the luminosities of the binaries could also be estimated. Deduced spectral types are in the range M2–M4.5. Preliminary modelling suggests that half the stars may be in contact configurations.

ОРГАНІЗАЦІЯ ПЛАНУВАННЯ РОЗВИТКУ ТЕРИТОРІЙ У КОНТЕКСТІ ДЕЦЕНТРАЛІЗАЦІЇ ДЕРЖАВНОГО УПРАВЛІННЯ: ПОЄДНАННЯ ІНТЕГРОВАНИХ, ПРОСТОРОВИХ ТА ЕКОНОМІЧНИХ ПІДХОДІВ

Досліджено комплексне просторове та економічне планування розвитку територіальних громад на умовах їх поєднання, яке сприятиме ефективному управлінню територіями і забезпеченню інтегрованого сталого розвитку територій для майбутніх поколінь. Висвітлено особливості законодавства щодо нових положень просторового й економічного планування територій територіальних громад, здійснено порівняння основних підходів до розроблення Комплексного плану просторового розвитку території територіальної громади, Концепції інтегрованого розвитку території територіальної громади і Стратегії розвитку громади. Побудовано схему зв’язків елементів при формуванні означених Комплексного плану, Концепції та Стратегії.Встановлено, що на законодавчому рівні прийнято положення щодо спільних підходів до формування ключових документів просторового і економічного планування розвитку територій територіальних громад, єдність документації із землеустрою та містобудівної документації на місцевому рівні.Показано, що Концепція інтегрованого розвитку території територіальної громади є основою й певним «містком» для поєднання засад і показників при формуванні Комплексного плану просторового розвитку території територіальних громад і Стратегії розвитку громади. Формування Концепції пропонується здійснювати на основі попереднього концептуально-структурного моделювання ендогенного потенціалу територіальних громад, з допомогою якого встановити особливості наявного потенціалу за його елементами (природно-ресурсним, виробничо-інфраструктурним, трудовим, соціально-культурним та ін.), що мають місце в кожній громаді залежно від її особливих і загальних характеристик.Доведено, що моделювання потенціалу територіальних громад здійснюється на основі встановлення, інтегрування, об’єднання, поєднання, взаємопроникнення зв’язків і залежностей у теперішньому часі та їх інтерпретації (проєктування, перенесення) на відповідну часову перспективу (п’ять, десять і більше років).

Numerical Analysis of the integrity of potential host rocks – modelling thermo-hydro-mechanical processes in the containment providing rock zone

Abstract. The disposal of heat-generating nuclear waste in deep geological formations is an internationally accepted concept. Several repository systems are under discussion in Germany, whereby claystone, salt or crystalline rock could act as the host rock. In this contribution we focus on repository systems where the Containment Providing Rock Zone (CRZ) ensures safe enclosure of the waste and thus the geologic barrier is essential. Even though the various rock types considered differ substantially in their mechanical, hydraulic, thermal and chemical behavior, they must all meet the same safety requirements as defined by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) in 2020. As part of these safety requirements, it must be shown that the integrity of the CRZ is guaranteed for the verification period, i.e. the retention of the properties essential for the containment capacities must be demonstrated over 1 million years. Therefore, the formation of new pathways must be avoided and temperature development must not significantly impair the barrier effect. The anticipated stresses and fluid pressures should not exceed the dilatancy strength and the fluid pressure capacity, respectively. In order to assess the compliance of these requirements, numerical modelling is an essential and powerful tool. Even though great progress has been made regarding the efficiency of computational methods, multiphysical modelling on different length scales over long time periods is still a challenging task. Moreover, since readily available solutions do not exist, adapted methods have to be developed and evaluated, in order to verify concepts and numerical implementations. The BGR gained experience in the field of thermal, hydraulic, mechanical (THM) numerical analysis of the integrity of the CRZ in salt rock and clay stone joined research projects on German disposal options. For crystalline rocks, first concepts are currently being developed within the CHRISTA II project. Compared to clay stone and salt rock, special features have to be taken into account: First of all, crystalline rock is characterized by fractures and other discontinuities. Thus, it cannot be assumed that an undisturbed area of sufficient size can be found for the entire nuclear waste. Consequently, several smaller CRZs must be defined, each providing undisturbed rock. Numerical analysis must deal with smaller CRZs and mechanical and hydraulic boundary conditions that are influenced by fractures. In addition, the processes in the individual CRZs may influence each other (e.g. Temperature distribution). Preliminary modelling approaches and results of numerical THM analyses, considering an upscaled fracture network, are presented.

EDNA metabarcoding as a means to assess distribution of subterranean fish communities: Iranian blind cave fishes as a case study

AbstractOne of the most important steps in conservation of the subterranean life forms is to decipher their distribution and ecology, which is challenging using traditional approaches. Development of an environmental DNA (eDNA) assay provides an efficient means for discovering and monitoring subterranean life forms. In this study, the distribution of three Iranian blind cave fish species (blind Iran cave barb Garra typhlops, blind Lorestan cave barb Garra lorestanensis, and blind cave loach Eidinemacheilus smithi) was assessed using 12S rRNA eDNA metabarcoding performed using MiFish‐U PCR primers and preliminary species distribution modeling (SDM) using bioclimatic data. The majority of sampling localities with positive detection of cave barb eDNA fall within suitable habitats in the Zagros Mountains of Iran. Our results revealed that Lorestan and Iran cave barbs have differential distribution patterns, with some extent of habitat overlap in the vicinity of the originally discovered cave barb locality. According to the observed distribution patterns, the blind Lorestan cave barb and cave loach are mostly distributed in habitats close to the Sezar River (Dez River drainage, Iran), and the blind Iran cave barb is distributed towards the west and probably in a few springs in the Karkheh River drainage. Our data support the previously proposed distribution pattern for the cave barbs, in which the species show partial niche separation and reproductive isolation, with the Lorestan cave barb being a water flow‐dependent species and the Iran cave barb being a generalist species preferring variable flow rates. We showed eDNA metabarcoding to be a useful approach for ecological surveys of subterranean fish biodiversity with implications for conservation.

ENHANCED MACHINE LEARNING METHODS FOR NONLINEAR HARMONIC SOURCE MODELLING

Power electronic-based devices inject harmonic perturbations in electrical networks and are thus a concern for network operators who must ensure that the harmonic injections and the resulting voltage disturbances are kept within acceptable limits. In this paper, we show that time domain (TD) methods can be useful in preliminary harmonic source modelling to derive the simulated models. Using TD SIMULINK models of our devices, we find the most influential internal and external parameters to be considered when the device is operating in a pre-existing harmonic environment and we generate datasets that can be used for training machine learning (ML) algorithms. We propose here three ML techniques to predict the harmonic currents originating from most widespread power electronic devices such as Light Emitting Diodes (LED) lamps and Electric Vehicle (EV) chargers, and compare them with TD models. The accuracy of all these models regarding their harmonic currents prediction capability is assessed under constantly evolving supply conditions.

Adaptive approach to engineering infrastructure reconstruction program and project management

Standard approaches to managing projects and programs for the reconstruction of engineering infrastructure in a turbulent environment are ineffective due to the lack of possibilities to adapt to external and internal influences. Therefore, the purpose of the article was to characterize the application of the conception of adaptivity in managing such projects and programs and to analyse the means for its application in management processes. The research presented in this article was conducted using scientific methods of critical analysis, systems analysis, mathematical modelling, formalization, analysis, synthesis, graphical and abstract-logical methods. The main constraints in the development of the program architecture were identified. The influence of the application of the standard approach to planning and managing programs and projects for the reconstruction of engineering infrastructure on the increase of the probability of risk emergence was investigated. The tasks of managing programs and projects in the implementation of management as the manifestation of control action were formulated. The concepts of active and passive methods of adaptive program management were considered, a combined method that involves preliminary modelling of managerial influences and learning from the experience of exerting such control actions was developed. The means of adaptive program management were analysed, the expediency of their use in the management of programs for the reconstruction of engineering infrastructure at different stages of their implementation was determined. The results of the study can be used by managers of programs and projects for the reconstruction or modernization of engineering infrastructure to determine approaches to management and selection of adaptive management tools for different phases of implementation, and also provide a methodological basis for further research

AN INVESTIGATION TURBULENCE MODEL OF STANDARD k- TO GET OPTIMUM PARAMETERS OF TURBULENCE CONSTANTS (cµ, c1, AND c2) OF COMPRESSIBLE FLUID DYNAMICS IN A CONFINED JET

This research aims to find the optimal standard k-e turbulence model constants (cµ, c1e, and c2e) for better predicting compressible fluid dynamics in an air jet ejector. The turbulence field in a jet flow plays an important role in influencing the performance of the momentum transfer process at a shear layer in nozzle application for momentum source and mixing process. In this research, some activities have been done before analyzing and optimizing the turbulence model constants, including preliminary turbulence modeling study for compressible flow in the air-jet ejector, verification, and validation with primary experimental data as well as by other secondary data. The preliminary studies in turbulence modeling presented that the turbulence modeling of a 3mm air jet-ejector resulted in a similar trend of the relation between entrainment ratio and motive fluid pressure. The results showed that the sensitive parameters in the standard k-emodel dissipation and diffusion terms, cµ, c1e, and c2e, strongly affected the optimum value of turbulence kinetic energy (k) and dissipation rate (e), compared to the reference model. Better k and e could be obtained by changing the c2e into positively proportional, but the cµ and c1e must be changed with opposite proportionality. It was found that the optimum standard k-e model constants in the case of air-jet ejector with 3 mm nozzle diameter for cµ, c1e, and c2e are 0.05, 1.48, and 1.88, respectively, with the error values for k being -8.88% and e being -17.44%.